Vacuum Drying Characteristics and Kinetics of Carrot Slices

The effect of the pressure and drying temperature on the drying characteristics of carrotslices was investigated.The results show that the drying-rate significantly depends on the pressure and drying temperature.For example, at a fixed pressure, the drying-rate increased with an increase of the temperature; and at a given temperature, the dryingrate increased with a decrease of the pressure.Fick's diffusion law well describes the moisture diffusion of carrot slices, and the effective moisture diffusion coefficient varied from 6.717 × 10^-10 to 18.594 × 10^-10 inthe temperature of interest.The activation energies of the carrot slices, 4 mm and 6 mm in thickness, were estimated with Arrhenius equation to be 31.46 and 33.06 k J/mol, respectively.Among the five thin-layer low temperature drying models available for data fitting in the non-linear regression method, Midilli and Kucuk model best fited the carrot slices drying.